CVE-2026-0556Network attack vector

Contributor-level stored XSS via unescaped shortcode attributes

Published Feb 19, 2026 · Updated Feb 19, 2026

Stored XSS in Xakuro XO Event Calendar 3.2.10 and earlier allows remote authenticated users to inject scripts via xo_event_field. The xo_event_field shortcode handler accepts user-supplied attributes without sufficient sanitization and returns their values in generated page output without context-appropriate escaping. Contributor-level access is sufficient to store the payload, which executes in visitors' browsers whenever an affected page is viewed.

CVSS severity6.4
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Xakuro XO Event Calendar 3.2.10 and earlier allows remote authenticated users to inject scripts via xo_event_field. The xo_event_field shortcode handler accepts user-supplied attributes without sufficient sanitization and returns their values in generated page output without context-appropriate escaping. Contributor-level access is sufficient to store the payload, which executes in visitors' browsers whenever an affected page is viewed.

The record

CVE
CVE-2026-0556
Published
Feb 19, 2026
Updated
Feb 19, 2026
Vendor
Xakuro
Product
XO Event Calendar
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=* <=3.2.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Xakuro · XO Event Calendarversion=* <=3.2.10

Published CVSS scores

6.4WordfenceCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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